The encapsulation of RF frequency components or functions has a plurality of objectives with regard to the external environment. In particular, it provides physical protection, electromagnetic protection and enables electrical interconnection with the exterior, in particular for linking them electrically to other components, to control signals and power supply sources via printed circuits.
A certain number of encapsulation techniques enable these objectives to be fulfilled in a more or less effective manner.
One of these techniques is known under the name “Ball Grid Array”, generally termed BGA technique. This technique consists of a package, the interconnection of which to the printed circuit is ensured by metal balls situated in a plane parallel to the surface of the components. One solution designed for RF frequency components, with a package ensuring good electromagnetic protection with regard to the exterior environment, is described in document FR 2 849 346.
One drawback of this solution is that the package has a large surface area, since it needs to comprise the components, but also their intermediate interconnection and the walls of the package.
Now, applications exist that impose severe spatial restrictions, such as for example transmitter and receiver modules of active type in which the grid is linked with the wavelength of the transmitted signals. In these cases in which the surface area available to receive the encapsulated components is restricted, the above solution is difficult to use. One known solution for overcoming this restriction problem is to use packages having a plurality of stages, thus reducing the surface area occupied on the printed circuit. Such a solution is in particular described in document FR 2 877 537. One drawback of this solution lies in the fact that it complicates the internal interconnection of the package.